Do I still need to bring a negative Covid test result for domestic flights even though I am fully vaccinated, or I need to show my vaccination card?

You just need a mask. They're not asking about anything else.

Just wear a mask.

No trestle needed for domestic flights. HI is different but CONUS is not required. Facemask is required.

You just need a mask for the moment

I didn't in salt lake. I assume it's the same in Boise... Just wear your mask